WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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Access Right: Closed AccessAuthor: search.filters.author.Polat, Nahit

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  • Article
    Citation - WoS: 5
    Citation - Scopus: 5
    Light-Induced, Liquid Crystal-Templated Fabrication of Large-Area Pure Nanoporous Gold Films With High-Density Plasmonic Cavities
    (Amer Chemical Soc, 2024) Orhan, Ozan Baran; Polat, Nahit; Demir, Seren; Balci, Fadime Mert; Balci, Sinan
    Nanoporous gold (NPG) films are three-dimensional gold (Au) frameworks characterized by a uniform distribution of nanoscale irregular pores. Typically produced via a dealloying process, where the less noble silver (Ag) is selectively etched out, NPG films offer a large surface area, excellent chemical stability, remarkable catalytic activity, unique optical properties, and biocompatibility. These attributes make them invaluable for applications in catalysis, plasmonics, biosensors, and nanophotonics. However, the presence of residual Ag from the dealloying process can limit their performance in certain applications. In this study, we report a novel method for the fabrication of ultrapure, large-area NPG films (several cm2) using a light-induced and liquid crystal-templated method. A hexagonal lyotropic liquid crystal containing a strong acid and a nonionic surfactant is combined with an aqueous solution of HAuCl4, followed by the photochemical synthesis of gold nanoparticles (NPs) within the liquid crystal. After calcination of the Au NP-containing liquid crystal film at high temperature, pure NPG films are produced. We demonstrate surface-enhanced Raman spectroscopy (SERS) of Rhodamine 6G (R6G) molecules adsorbed on the NPG films and detect extremely low concentrations (below 10-6 M) of R6G. Additionally, we thoroughly investigated the formation and optical properties of the NPG films. The results reveal that the ultrapure NPG films contain high-density plasmonic nanocavities, where substantial electromagnetic fields are generated, leading to significant enhancement of optical processes at nanoscale dimensions.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Room Temperature Emission From Single Defects in Wo3 Enhanced by Plasmonic Nanocrystals
    (American Institute of Physics, 2021) Özçeri, Elif; Polat, Nahit; Balcı, Sinan; Tarhan, Enver
    Room temperature light emission from optically active defect centers in two-dimensional layered materials has attracted great interest in recent years owing to the critical applications in the field of quantum information technologies. Therefore, efficient generation, detection, characterization, and manipulation of spatially localized emission from the defect centers are of crucial importance. Here, we report localized, stable, and bright room temperature photoluminescence (PL) emission from defects in WO3. In particular, the experimentally observed polarized and power dependent PL emission shows single photon characteristics. In addition, density functional theory calculations indicate that the source of the emission is most probably oxygen vacancy defects in WO3. The PL emission obtained from the localized defect centers in WO3 at room temperature has been, further, enhanced more than 20 times by using plasmonic gold nanoparticles.
  • Article
    Citation - WoS: 35
    Citation - Scopus: 36
    Colloidal Nanodisk Shaped Plexcitonic Nanoparticles With Large Rabi Splitting Energies
    (American Chemical Society, 2019) Mert Balcı, Fadime; Sarısözen, Sema; Polat, Nahit; Balcı, Sinan
    When plasmons supported by metal nanoparticles interact strongly with molecular excitons or excitons of semiconducting quantum dots, plexcitons are formed in the strong coupling regime. The hybrid plexcitonic nanoparticles with a wide range of sizes and shapes have been synthesized by using wet chemistry methods or have been fabricated on solid substrates by using lithographic techniques. In order to deeply understand plasmon-exciton interaction at the nanoscale dimension and boost the performance of nanophotonic devices made of plexcitonic nanoparticles, new types of plexcitonic nanoparticles with tunable optical properties and outstanding stability at room temperature are urgently needed. Herein, we for the first time report pure colloidal nanodisk shaped plexcitonic nanoparticles with very large Rabi splitting energies, i.e., more than 350 meV. We synthesize silver nanoprisms by using seed mediated synthesis and then convert nanoprisms to nanodisks at a high temperature. Localized plasmon resonance of the silver nanodisk in the visible spectrum can be effectively tuned by heating. Subsequently, self-assembly of J-aggregate dyes on plasmonic nanodisks produces plexcitonic nanoparticles. We envision that colloidal nanodisk shaped plexcitonic nanoparticles with very large Rabi splitting energies and outstanding stability at room temperature will enlarge the application of plexcitonic nanoparticles in a variety of fields such as polariton laser, biosensor, plasmon molecular nanodevices, and energy flow at nanoscale dimensions.